Deterministic and Recursive Approach in Attitude Determination for InnoSAT

Abstract: Attitude
determination system (ADS) was indispensable in attitude control of satellite.
Especially for InnoSAT due to the limitation of budget, weight, and power, the
attitude was determined using onboard position sensors. Previous research has
successfully implemented the attitude determination using only Earth's magnetic
field sensors for small attitude angle, but the approach produced quite big
error for large attitude angle. This paper presents attitude determination for
InnoSAT using combination of sun sensors and earth's magnetic field for large
attitude angle. The attitude was determined using a deterministic (QUEST) and
recursive (EKF) approach. A problem arises when using the sun sensors while the
satellite experiencing eclipse. Consequently, the accuracy of both approaches
was analyzed at eclipse and no eclipse conditions. The result shows that
deterministic approach produced better accuracy at no eclipse but recursive
approach produced better accuracy at eclipse. The strategy to apply the both
approaches and eclipse conditions also discussed in this paper.